Special service telephone system



Feb.. 27, 1945. Q, A, FRlEND i 2,370,239

SPECIAL SERVICE TELEPHONE SYSTEM Filed Jan. 13, 1'944 5 sheets-sheet 1- .2 PRE-PAY an@ Feb. 27, 1945. I Q A FRlEND' 2,370,239

l SPECIAL SERVICE TLPHONE SYSTEM Filed Jan. 13, 1944 l5 sheets-sheet 2 l F/ c. 2

SPEC/AL LINE FNDE REGULAR Ll/E F/Nasn srmr Luo www V G la m /NVE/v ro@ O. A. F R/E ND BV ATTORNEY NICKEL BEFORE DIAL TONE Feb. 27, 1945. o. A. FRIEND 2,370,239

K SPECIAL SERVICE TELEPHONE SYSTEM Filed Jan. 13, 1944 5 Sheets-Sheet 5 IlT ATTORNEY Feb. 27, 1945. o. A. FRIEND SPECIAL SERVICE TELEPHONE SYSTEM 5 Sheets-Sheet 4 Filed Jan. 13, 1944 A 7' TOR/M5 V Feb. 27, 1945. Q A; FRlEND 2,370,239'

SPECIAL SERVICE TELEPHONE SYSTEM Filed-Jan. 13, 1944 5 Sheets-Sheet 5 De s ju S I l Il ll QS t. z: u.

INVENTOR QAFR/END A TTORNE Y Patented Feb. 27, 1945 UNITED STATES rPATENT OFFICE SPECIAL SERVICE TELEPHQNE SYSTEM Otto A. Friend, New York, N. Y., assigner to Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application January 13, 1944, Serial No. 518,073

3 Claims.

This invention relatesv to telephone systems and particularly to special service arrangements for.

prise the calling subscriber of such temporary i emergency condition and to return the deposited coin.

It will be recognized that this operation may be carried out in a great many Ways and that numerous modifications of the specic means shown herein are contemplated as being within the scope of the present invention, due to the many types of telephone systems in use.

By way of example, where coin boxes are arranged so that the deposit of a coin operates the line relay the operation will be as follows. With all regular line nders of a group busy the normal line-finder start lead will be transferred to the special line finder. If a coin is then deposited to originate a call, the corresponding line relay will operate and cause the special line nder to find and cut through to the line in the same manner as a standard line finder. The associated coin return equipment will apply coin return battery for a short interval followed by a special tone for a short interval or the tone and coin return battery may be applied in the reverse order or even simultaneously. Each of these operations may be done by well-known means. After these operations are completed the line finder returns to normal and if other line relays are operated the finder will proceed as above set forth for each of the lines involved.

Again, by way of example, where coin boxes are arranged so that the line relay is operated whenever a receiver is 01T the hook regardless of whether or not there is a coin in the box a different specific arrangement would be provided. With this type of coin box .a line relay would remain operated after coin return if the calling subscriber failed to hang up. As a result the special line nder must be prevented from repeatedly connecting to the same line to the exclusion of other lines. In order to meet this situation, a cruising line nder is employed which will-have the previously described coin return and tone functions but will connect to lines with operated line relays in definite sequence in the following manner. When rst called into operation, the

special equipment will first serve thetnearest calling line on the lowest level. After completing its functions on this line as previously described,vthe nder will not release but will step to the next calling line on the same level. After all lines on this level have been served the nder will release. The level will be marked either by the operation of a marking relay or a recording switch. If calls are still waiting the nder will start again and will cut in on the next level. In

this manner the nder will serve all levels by continuing to cruise as long as there is an operated line relay and applying coin return battery and tone to each line with an operated relay.

To avoid excessively frequentoperation due to one or more lines with receivers off the'hook (or permanent signals) the circuit may be arranged' so that intervals between the restarting operation are not less than a predetermined amount, 'y

for instance, thirty seconds. l

A feature of the invention is a means responsive to the lack of normal facilities for connecting with a line and performing a special operation thereover. 'n

Another feature of the invention is a' special lineiinding arrangement for connecting with a turn a deposited coin and to apprise the calling subscriber of the said temporary emergency condition.

Another feature of the invention is a specialy .line nder which under temporary emergency conditions will cruise over the lines to which it may connect and to connect with different ones in turn to perform a, special emergency operation thereover.

Other features will appear hereinafter.

The drawings consist of ve sheets having eight figures, as follows:

Fig. 1 is a schematic circuit diagram helpful in explaining the principle of operation in connection with prepayment coin service systems;

Figs. 2 and 3, when placed' as shown in Fig. 4, provide a more complete circuit diagram of the form of the invention shown in Fig. 1;

Fig. 5 is a schematic circuit diagram similar to that of Fig. 1 showing an alternative form of the invention; and Figs. 6 and '7, when placed as shown in Fig. 8,

provide a more complete circuit diagram of th form of the invention shown in Fig. 5.

In the arrangement shown in Fig. 1, the subscriber at station l cannot operate the central cnice apparatus until he has deposited a coin 2. The weight of this coin on an arm 3 will close the contacts 4 and 5 of the coin disposal magnet. At the central oice the subscribers line circuit 8 will respond to a grounded tip, the start circuit 9 will be energized and a regular line finder indicated in the broken line rectangle I will respond and make a connection to the line in a manner well known.

Under emergency conditions, however, and either when the all nders busy circuit I I grounds the conductor I2, or the line load control key I3 is operated by the proper authority, the special start circuit I4 will be operated, whereupon a special line i'lnder indicated in the broken line rectangle I will make connection tothe line and the circuit in the broken line rectangle I6' will apply coin return battery and tone to the line. Any coin in the coin chute will then be returned. If the subscriber is still on the line, the tone applied will notify him that his coin is being returned since an emergency condition exists. As soon as the subscriber hangs upl the special line iinder will be released. Details of this operation will be understood Ithrough the. following descrip`- tion of Figs. 2 and 3.

The subscribers circuit is conventional, Theoperation of the hook switch I1 will close through a talkingcircuit to the line wires but the line circuit at the central oice will not respond until the tip Wire` isl grounded by the deposit of a coin. When a coin; has been deposited a circuit is established from ground, contactsr I 6, winding of coin disposal magnet I6, tip wirev -r back contact and armature I of cut-oii' relay 2l, winding of line relay 22 to battery. Line relay 22 responds and closes a circuit from ground, front contact and armature I of relay 22, armature I and back contact o! transfer relay 23,v winding of group relay 24 to battery. Relay 24 grounds the start lead 25- and grounds a particular level contact 26 of the line finders which will respond Ito. the ground on start lead 25. The operation of this apparatus is well-known andwill not be. further described.

An all finders busy circuit is indicatedI in the broken line rectangle 21. When all the nders availableV are vbusy this circuit will place ground on conductor 29 in a manner well known. When conductor 26 is grounded either by the all finders busy circuit 21 or-by the linev load key 28 the transfer relay 23 will be operated. Under this condition if a call is made a connection is established from ground, front contact and armature I of relay 22,` armature I and front contact of transfer relay 23 to the-winding of start relay 36. Relay 3llbecomes energized and through its armature 2 places a ground on start conductor 3I I vertical magnet 31, armature l and back contact A of rotary magnet 38, lower Winding of relay 36,

back contact and armature 4 of relay 32 to battery. Relay 36 operates and closes a circuit for the vertical magnet 31 from ground, armature 3 and front contact of relay 35, armature and front contactof relay 36, armature 2 and back contact of relay 39, winding of Vertical magnet 31,

back contact and armature 4 of relay 32 to battery. The vertical magnet 31 is thus placed in a self-operating circuit, for as magnet 31 operates it opens the circuit of relay 36 and relay 36 in turn opens the circuit of magnet 31. Thereupon magnet 31 releases and closes lthe circuit for relay 36. Therefore, as long as there is no interference to this action magnet 31 and relay 36 will interact and magnet 31 will lift the brushes 40, 4I, 42 and 43 step by step. When brush 4U nds a ground, as on segment 44, from relay 30, it will cause relay 39 to operate. through its lower winding, armature I and back contact of rotary magnet 38, lower winding of relay 36, back contact and armature 4 of relay 32 to battery. This will hold relay 36 operated and when magnet 31 releases after the movement which placed brush 40 on segment 44 will close a circuit through the winding of vertical magnet 31 and the upper Winding of relay 33, front con-tact and armature 3 of relay 39, front contact and armature 3 or relay 35 to ground. Magnets 31 and 38 do not energize in this circuit but relay 39 does energize. This will prevent further vertical stepping of the switch.

The rotary magnet 36 is now energized in a circuit from ground armature. 3 and 'front contact of relay 35, armature` and front contact of relay 36, armature 2 and front contact of relay 39, winding of rotary magnet 38Y to battery. As rotary magnet 38 energizes relay 36 is deenergized, whereupon the circuit for rotary magnet 38 is opened. By this interaction the brushes 4l. 42. and 43 are stepped around in a rotary direction until the brush 4i encounters a calling conditionl. When this is found a circuit may be traced from ground, armature 2 and front contact of relay 35, upper winding of relay 36, armature I and back contact of relay 32, upper winding of relay 45, brush 4I sleeve terminal 46, front contact and armature 2 of transfer relay 23 armature 2 and front contact of line relay 22,

.winding of out-ofi relay 2l to battery.

relay also closes a circuit for relay 32 which in i turn opens the circuit through the upper Winding of relay 45. The circuit for the energization of relay 32 may be traced from ground, springs 3 and 2 of the vertical off-normal contacts 41 operated on the first vertical step of the switch,

. front contact and armature 5 of relay 45, winding of relay 32 to' battery. Relay 35 is now deenergized by the movement of armature 3 of relay 32 but being slow to release momentarily establishes a circuit from ground, armature 2 and front contact or relay 35, front contact and armature I of relay 32 (which short-circuits the upper winding of relay 36), armature 3 and front contact of relay 45 and thence over the circuit traced to the cut-off relay 2| which causes the energization of this relay and the consequent release of the' line relay 22. The energization of the cut-o relay 2l provides a direct path from the armature 2 of transfer relay 23 when the line relay releases. Before relay 35 can open this ground connection to the sleeve wire 46 a substitute ground will be returned from the circuit of Fig. 3 as will be described hereinafter. It should be noted, however, that if now or later the ground on conductor. 29 is removed as by the release of key 28 or the action of the all finders tacts 41, front contact and armature of relay 45, and when relay 35 releases in parallel therewith through the back contact and armature I of relay 35. Relays 36, 39 and the stepping magnets of the switch are released and the switch remains set with only relays 32 and 45 energized. Upon the release of the line relay 22 the group relay 30 is released.

Upon energization of relay 45, the tip and ring conductors of the line now connected to brushes 43 and 42, respectively, are extended by armatures I and 2 of relay 45 to the coin return and tone circuit of Fig. 7. Here a circuit may be traced from the tip conductor 49 over armature 2 and back contact of relay 5I, the upper Winding of line relay 52 to battery and from the ring conductor 50 over armature 3 and back contact of relay 5I, the lower winding of line relay 52 to ground. Either a groundon the tip as from a deosited coin or a low resistance connection between the tip and ring as from the operation of the switchhook I1 will cause the energization of the line relay 52. This relay grounds the hold relay 53 and relay 53 in turn grounds the sleeve Wire 48 through its armature 2 and operates relay 5I through its armature I. The circuit for relay 5I extends through the armature and-back contact of relay 54 to ground. Relay 5I in operating causes the energization of relay 54 and relay 54 in operating opens the circuit of relay 5I. However, relays 5I and 54 are slow releasing so that relay 5I does remain operated for a short period. During this period the tip and ring conductors are disconnected from the line relay 52 and alternatively connected to coin return battery 55. Any coin at the substation will be returned. Now upon the release of relay 5I the ground on the tip has been removed and the line relay will fail to reoperate unless the subscriber has failed to hang up. A source of tone may be connected by conductor 56 to one winding of the line relay 52 so that such a tone will be connected intermittently to the subscribers line to notify him that an emergency condition exists and that there is no apparatus available to extend his connection. If after the coin has been returned by the energization of relay 5I when relay 5| next releases the line relay fails to reoperate, the hold relay 53 will be released and since ground is now removed from sleeve conductor 48 the special inder will be released. The removal of ground from conductor 48 releases relays 45 and 32 and establishes a circuit for release magnet 51 from ground, springs 3 and 2 of off-normal contacts 41, back contact and armature I of relay 35, armature 5 and back contact of relay 45 back contact and armature I of relay 39, springs 4 and 5 of off-normal'contacts 41 winding of release magnet 51 to battery.

In the coin return and tone circuit of Fig, 3 a timing device relay is operated from the hold relay 53. The relay 58 is rendered slow to oper- -ate so that under normal operating conditions for relay 53 the relay 58 will not respond. However, if the application of coin return battery to the tip does not result in the removal of ground from the tip orif the subscriber does not hang up within a reasonable time or under any other emergency or trouble condition the line relay reoperates each time relay 5I releases, then relay 58 will operate and will energize an alarm circuit 6I. A switch 62 is provided to short-circuit the upper armature and back contact of relay 58. With this switch closed the coin return and tone circuit will be held until an attendant responding to the alarm circuit clearsy the trouble. With this switch open, the operation of relay 58 removes ground from the sleeve and releases the special apparatus. The alarm circuit may in this case be arranged to record the trouble. If the trouble on the line persists the special nder will be repeatedly called into service. In order to prevent unduly frequent operation and to give the special iinder opportunity to service other lines the condenser 59 and resistance 60 network may be provided to hold the relay 58 operated for any given period.

Another form of the invention is shown in Figs; 5, 6 and 1. In this case the coin does not have to bedeposited until after the dial tone is received. Despite this subscribers sometimes deposit a coin before this time and hence the arrangement .of Figs. 5. 6 and -7 is provided to return such coins erroneously deposited under emergency conditions. In accordance with the schematic of Fig. 5 a subscriber at station 1D may make a call by merely operating his switchhook. His line circuit 1I at the central oiice will respond and by grounding the start wire 12 will operate the start circuit 13 which in turn will cause a regular finder indicated -by the broken line rectangle 14 to extend his line to the selective switches which he may then operate in a conventional manner. As in the arrangement shown in Fig. l, if the all nders busy circuit 15 or the line load key 15 grounds the start wire 11 then a special finder indicated by the broken line rectangle 18 will operate to cause the coin return circuit indicated by the broken line rectangle 19 to apply coin return battery to the` line. In this case a cruising line finder will be employed to lgo over all the lines in trouble in turn and not to repeatedly connect to one line to the exclusion of others. The action of this special finder will be explained in detail hereinafter.

Considering the more detailed circuits of Figs. 6 and 7, when the telephone 8l) is removed from the switchhook SI, the line relay 32 at the centrai office will respond. The presence or the absence of a coin in the chute to operate the convtacts 83 does not affect this operation in any way.

conditions to ground the start lead 39 the cruis` ing finder in the lower righthand portion of Fig. 6 will be started in operation. Ground on lead 89 will-be used to operate the start relay 90. This will establish a connection from ground front contact and armature of relay 9D, armature 3 and back contact of relay QI contacts I and 2 of the spring combination 93 operated at the switch has taken ten rotary steps, Winding of relay 92 to battery. Relay 92 operates and 91, winding'of vertical magnet 94, back contact.

and armature 4 of relay 9| to battery. Magnet 94 and relay 90 are in mutually controlling circuits whereby magnet; 94 will step the brushes of the switch until stopped by a condition estab-- lished by brush 98. This condition is one established under control of wiper 99 controlled by the stepping magnet |00. When brush 98 encounters a segment which at the time is connected through the wiper 99 to ground a circuit through the lower winding of relay 91, armature I and back contact of rotary magnet 95, lower Winding of relay 9B, back contact and armature 4 of f relay 9| is established, with the result that relay 91 is energized and relay 99 is prevented from releasing. Relay 91 now locks through its upper winding, front contact and armature 3 of relay 91 contacts 4 and 3 of spring combination 93, contacts `2 and 3 ofthe vertical off-normal spring combination |02 to ground. Thereupon a circuit is established for rotary magnet 95 from ground armature 3 and front contact of relay 92, armature and front Contact of relay 95, armature and front contact of relay 91 winding of rotary magnet 95 to battery. Since magnet 95 controls the circuit of relay 95 by its armature I and since relay 99 controls the circuit of magnet 95 these two devices will interact until a calling line is encountered. Thus the brushes |03, |04 and |05 will be rotated step by step-until brush |03 encounters terminal |06 whereupon a circuit is established from ground, armature 2 and front contact of relay 92 upper Winding of relay 96, armature-| and back contact of relay 9|, upper winding of relay |01, brush |03, terminal |06, armature 2 and front contact of line relay 82, winding of cut-oil relay |08 to battery. Relay |01 responds and operates relay 9| from ground, front contact and armature 6 of relay |01, winding of relay 9| to battery. Thereupon a temporary circuit, for the release time of relay 92 is established from ground, armature 2 and front contact of relay 92 sleeve wire |09, front contact and armature of relay 9|, armature and front Contact of relay |01, brush |03, terminal |06, armature 2 and front contact of line relay 82, winding of cut-off relay |08 to battery. Cut-off relay |08 operates and locks its armature 3 and front contact independently of line relay 82 which now releases. The ground `placed on sleeve wire |99 also locks relay |01 through its armature 4 and front contact and its lower winding. Also upon the operation of relay |01 its upper wndingis rst short-circuited through the back contact and armature of relay 9| and then opened as relay 9| operates. The ground supplied to the sleeve conductor |09 by relay 92 is replaced by a ground from the coin tained energized so that further rotary movement may take place.

Upon the operation of relay |01 the tip andring conductors of the calling lineare extended through armatures and 2 of relay |01 to tip and ring conductors and ||0 respectively. These may be traced through armatures 2 and. I

of relay ||2 to the upper and lower windings of line relay ||3 respectively whereupon this relay will operate. The operation of relay ||3 resulta in the operation of relay ||4 which closes a circuit through the winding of relay I I2 to the back contact and armature of relay ||5 to battery. Relay ||2 operates and closes a circuit for relay 5 but both these relays being slow to release vwill cause the application of coin return battery ture 2 and front contact of relay ||5, winding of relay ||5 to battery to lock in this last relay so that in this case the coin return battery is 'applied to the calling line but once and then when relay ||2 releases the tone is applied thereto until the slow operate relay |20 operates. When this happens the ground is removed from sleeve conductory |09 and the special finder is released.

It will be noted that upon the removal of ground from conductor |09, relays 9| and |01 will release. Thereupon a circuit is again established for relay 92, providing relay 90 is still energized. Hence the rotary magnet is again energized as before so that the brushes will rotate over the remainder of the level on which it has already beenset. If another calling line is found on this level the actiony above described will be repeated. If no other calling line is found then' the circuit of the A relay 92 is broken and the holding circuit of relay 91 is opened by the movement of spring combination 93 as the brushes move off their tenth set of contacts. With relay 92 released a circuit is established from ground, contacts 3 and 2 of spring combination |02, back contact and armature of relay 92, armature 5 and back contact of relay |01, back contact and armature of relay 91, contacts 4 and 5 of springv combination |02, winding of release magnet |2|, and winding of advance relay |22 to battery.

, The release magnet |2| will 'release the switch to normal and relay |22 will transmit an impulse 89 is grounded.

If the ground is removed from the start'wire before the switch has reached a calling line, then the A relay 92 will be released and the switch will be halted and released without completing its hunting operation.

It will be readily apparent that other combinations coming within the scope of the present invention can be produced.

What is claimed is:

l; In a check controlled dial telephonesystem.

apparatus for extending connections from a calling line, a line nder responsive to an incoming call during the busy condition of 'all available said apparatus for establishing a circuit connection thereto, and means in said -circuit connection for controlling the refunding of a deposited check.

2. In a check controlled dial telephone system, apparatus for extending connections from calling lines, a line nder responsive to one or more incoming calls during the busy .condition of all available said apparatus for successively establishing a circuit connection to said calling lines, and means in said circuit connection for causing the return of all checks deposited in connection with said calling lines.

3. In a check controlled dial telephone system,

apparatus for extending connections from calling lines, a line nder responsive to one or more l incoming calls during the busy condition of all available said apparatus for successively establishing a circuit connection to said calling lines, a source of check return battery, and a source of tone in said circuit connection, and means for applying said sources to a calling line upon the establishment of a connection thereto by said line nder.

OTTO A. FRIEND. 

